Vented plastic film and method of making

Abstract

Vented plastic stretch film and a method of making the film in which elongated reinforcement strips are applied to a base sheet, each reinforcement strip including a cord-like, reinforcement member formed from plastic film and a flat, narrow film strip covering the reinforcement member. Vent holes are formed from slits between the reinforcement members by applying tensional forces to the base sheet.

The invention claimed is: 
     
       1. A method of producing vented plastic stretch film, said method including the steps of:
 providing an elongated base sheet of plastic stretch film having a longitudinal axis; 
 transporting the elongated base sheet in a direction of movement corresponding to the longitudinal axis of said elongated base sheet; 
 simultaneously with the transport of said elongated base sheet, forming a plurality of cord-like, elongated reinforcement members, where each of said cord-like, elongated reinforcement members is made by simultaneously randomly compressing a transported flat, narrow plastic film strip by randomly compressing said flat, narrow plastic film strip by rotating a collector roll and employing a compressor nozzle during transport thereof; 
 during transport of said elongated base sheet, attaching said plurality of cord-like, elongated reinforcement members to said elongated base sheet, said cord-like, elongated reinforcement members extending along the longitudinal axis of said elongated base sheet, spaced from one another and disposed substantially parallel to one another; 
 transporting said elongated base sheet and said cord-like, elongated reinforcement members attached thereto in the direction of movement to the longitudinal axis of said elongated base sheet; 
 during transport of said elongated base sheet and said cord-like, elongated reinforcement members attached thereto, positioning a narrow plastic film strip overlay over each of said cord-like, elongated reinforcement members, said narrow plastic film strip overlays being parallel and spaced from one another; 
 attaching said narrow plastic film strip overlays to said cord-like, elongated reinforcement members and to said elongated base sheet to fixedly sandwich said cord-like, elongated reinforcement members between said elongated base sheet and said narrow plastic film strip overlays, said narrow plastic film strip overlays and said cord-like, elongated reinforcement members comprising parallel, elongated reinforcement strips defining elongated spaces therebetween, said base sheet being uncovered in said elongated spaces; and 
 during transport of said elongated base sheet and said elongated reinforcement strips, forming a plurality of slits in said elongated base sheet in the elongated spaces defined by said elongated reinforcement strips and applying tensional forces to said base sheet to stretch said elongated base sheet and expand and open said slits to form vent holes therefrom, said elongated reinforcement strips operable to restrict formation of said vent holes to the spaces defined thereby. 
 
     
     
       2. The method according to  claim 1  wherein said slits are substantially centered in the spaces defined by said elongated reinforcement strips. 
     
     
       3. The method according to  claim 1  wherein said slits are separated from one another and oriented transversely relative to the longitudinal axis of the elongated base sheet and to the elongated reinforcement strips. 
     
     
       4. The method according to  claim 1  wherein the step of forming a plurality of vent holes includes applying tensional forces to said base sheet to stretch said base sheet and expand and open said slits for form the vent holes when said vented plastic stretch film is being stretch wrapped about one or more objects. 
     
     
       5. The vented plastic stretch film obtained by the method of  claim 1 . 
     
     
       6. Vented plastic stretch film including, in combination:
 an elongated base sheet of plastic stretch film having a longitudinal axis; and 
 a plurality of elongated reinforcement strips, each elongated reinforcement strip including a cord-like, elongated reinforcement member comprising a randomly compressed flat, narrow plastic film strip attached to said elongated base sheet and extending along the longitudinal axis of said elongated base sheet, the cord-like, elongated reinforcement members of the plurality of elongated reinforcement strips being spaced from one another and parallel, each said elongated reinforcement strip further including a narrow plastic film strip over the cord-like, elongated reinforcement member thereof, said narrow plastic film strip being attached to the cord-like, elongated reinforcement member and to the elongated base sheet at opposed sides of said cord-like, elongated reinforcement member to fixedly sandwich the cord-like, elongated reinforcement member between the elongated base sheet and narrow plastic film strip, said elongated reinforcement strips extending along the longitudinal axis of said elongated base sheet, disposed substantially parallel to one another, and defining elongated spaces therebetween, said base sheet being uncovered in said elongated spaces and defining a plurality of slits in said elongated spaces, said elongated reinforcement strips operable to prevent enlargement of said slits beyond the spaces defined thereby.